The present invention relates to armrest supports and in particular to armrest support which are adjustable in height and allow adjustment of the angle of the armrest support.
Many different types of adjustable armrest support have been proposed where the armrest is adjustable in height as well as angle. Some of these structures have a single lock mechanism that allows adjustment of both height and angle by release of a single lever.
A common approach is to use a lock arrangement having at least one pin receivable in any hole of a series of holes for locking of the armrest column at a particular height. With this type of structure, there is a separate armrest angle adjustment provided at the top of the armrest support for varying the angle of the armrest relative to the axis of the column support. A lever and control linkage arrangement allows for release of the lock mechanism to allow adjustment of the height of the column support.
U.S. Pat. No. 5,749,628 discloses a spring loaded pawl member engageable with a ratchet surface provided on the exterior of a column to allow adjustment of the height of the arm. The pawl is spring loaded against the ratchet surface and is moveable by means of a lever to a release position. The angle adjustment of the arm is provided by a separate locking arrangement provided at the top of the column. The adjustable arm of U.S. Pat. No. 5,749,628 uses a support column of a rectangular configuration with the arm holder slideable on this rectangular bar configuration. With this arrangement all adjustment of the arm must occur at the top surface of the adjustable arm support.
There are a series of adjustable height armrest supports which have a first lock arrangement for adjusting and locking the height of the armrest and a spring detent type lock arrangement provided at the upper surface of the column. Basically the arms are free to assume a different angular position if sufficient force is applied to move the spring detent from one locking position to a different locking position.
It is desirable to provide a simple height adjustable armrest support which also accommodates adjustment in the angle of the armrest. Furthermore, it would be desirable to provide such a system which can be adapted to accommodate different mounting angles of the armrest relative to the chair seat. Thus the armrest can be angled slightly outwardly or inwardly as well as forwardly and rearwardly as necessary for a particular style of chair.
An adjustable in height armrest according to the present invention comprises a tubular armrest column, a tubular armrest carrier adapted to telescope relative to the armrest column for adjusting the height of the armrest, an arm support located on top of said armrest carrier and a releasable locking system for securing the armrest column relative to the armrest carrier in one of a series of positions where each position defines a fixed height of the armrest and a fixed angular orientation of the arm support relative to a longitudinal axis of the armrest column. With this arrangement, the height of the armrest and the angle of the arm support relative to the longitudinal axis of the armrest column are adjustable. The releasable locking system includes two locking members carried by the armrest carrier and releasably engageable with locking recesses provided in an outer surface of the armrest column on opposite sides thereof. The locking system further includes a lock release member having a spring bias urging said lock release member to a locking position, said lock release member in said locking position forcing said locking members into engagement with said locking recesses to secure said armrest at a fixed height and angle. The lock release member when moved against the spring bias to a release position frees the locking members to move and disengage said locking recesses thereby allowing adjustment of the height and angular position of the arm support about the axis of the tubular armrest column.